find c when D=12: First you have to plug in the number so if d=12 the you do c=12(1.5) which equals 18. C=18
Find d if C=15: you now have to do the inverse operation. if c=d1.5 then d= c/1.5 Then plug in the numbers again, d=15/1.5 it equals 10, so d=10
I hope this helps (: